#include<stdio.h>
#include<string.h>
int judge(char);
int main()
{
	char str[80];
	int flag;
	int length;
	int i;
	
    scanf("%s", str);
	length = strlen(str);
	if (length % 2 == 0) {
		for (i = length / 2; i < length; i++) {
			if (str[i] != str[-i + length - 1]) {
				flag = 0;
				break;
			}
			else
				flag = 1;
		}
		
	}
	else {
		for (i = (length / 2) + 1; i < length; i++) {
			if (str[i] != str[-i + length - 1]) {
				flag = 0;
				break;
			}
			else
				flag = 1;
		}
		
	}
	if (flag==1)
		printf("yes");
	else
		printf("no");

	return 0;
}
